Ch 7 Section 1 Flashcards
common names usually give no information about
chemical composition
to describe atomic makeup of compounds chemists use
systematic methods for naming compounds and for writing chemical formulas
for a molecular compound, the chemical formula reveals the number of atoms of each element contained in a
single molecule of the compound
an ionic compound consists of a lattice of
positive and negative ions held together by mutual attraction
the chemical formula for an ionic compound represents one formula unit–the
simplest ratio of the compound’s positive ions and its negative ions
parentheses surround the polyatomic anion to
identify it as a unit
when there is no subscript written next to an atom’s symbol, the value of the subscript is
understood to be 1
monatomic ions are ions formed from a
single atom
not all main-group elements readily
form ions
atoms of carbon and silicon form
covalent bonds in which they share electrons with other atoms
other elements tend to form ions that do not have
noble-gas configurations.
elements from the d-block form
2+, 3+, 1+, or 4+ cations
Many d-block elements form two
ions of different charges
monatomic cations are identified simply by
the elements name
in naming monatomic anions the ending of the element’s name is
dropped and replaced with -ide
numerals used in the naming of ions are part of the
stock system of naming chemical ions and elements
binary compounds are compounds composed of
two elements
in a binary ionic compound the total numbers of positive charges and
negative charges must be equal
the formula for a binary compound can be written given the
identities of the compound’s ions
in binary ionic compounds the charges of the compounds are not
included in the formula
crossing over is a method of balancing the
charges between ions in an ionic compound
Step 1 for cross over method
write the symbols for ions side by side, with cation first
step 2 for cross over: cross over the
charges by using the absolute value of each ion’s charge as the subscript for the other ion
step 3 for cross over: check the subscripts and divide them by their
largest common factor to give the smallest possible whole-number ratio of ions. then write the formula
nomenclature
naming system
the nomenclature of binary ionic compounds involves combining the names of the
compound’s positive and negative ions
for most simple ionic compounds, the ratio of the ions is not indicated in the compound’s name because it is
understood based on the relative charges of the compound’s ions
some elements form two or more
cations with different charges